Messages in this thread | | | Date | Fri, 10 Mar 2023 11:30:04 +0800 | Subject | Re: [PATCH 08/12] iommufd/device: Report supported hwpt_types | From | Baolu Lu <> |
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On 3/9/23 4:09 PM, Yi Liu wrote: > This provides a way for userspace to probe the supported hwpt data > types by kernel. Currently, kernel only supports IOMMU_HWPT_TYPE_DEFAULT, > new types would be added per vendor drivers' extension. > > Userspace that wants to allocate hw_pagetable with user data should check > this. While for the allocation without user data, no need for it. It is > supported by default. > > Co-developed-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Nicolin Chen <nicolinc@nvidia.com> > Signed-off-by: Yi Liu <yi.l.liu@intel.com> > --- > drivers/iommu/iommufd/device.c | 1 + > drivers/iommu/iommufd/hw_pagetable.c | 18 +++++++++++++++--- > drivers/iommu/iommufd/iommufd_private.h | 2 ++ > drivers/iommu/iommufd/main.c | 2 +- > include/uapi/linux/iommufd.h | 8 ++++++++ > 5 files changed, 27 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c > index 19cd6df46c6a..0328071dcac1 100644 > --- a/drivers/iommu/iommufd/device.c > +++ b/drivers/iommu/iommufd/device.c > @@ -322,6 +322,7 @@ int iommufd_device_get_hw_info(struct iommufd_ucmd *ucmd) > > cmd->out_data_type = ops->driver_type; > cmd->data_len = length; > + cmd->out_hwpt_type_bitmap = iommufd_hwpt_type_bitmaps[ops->driver_type]; > > rc = iommufd_ucmd_respond(ucmd, sizeof(*cmd)); > > diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c > index 67facca98de1..160712256c64 100644 > --- a/drivers/iommu/iommufd/hw_pagetable.c > +++ b/drivers/iommu/iommufd/hw_pagetable.c > @@ -173,6 +173,14 @@ static const size_t iommufd_hwpt_alloc_data_size[] = { > [IOMMU_HWPT_TYPE_DEFAULT] = 0, > }; > > +/* > + * bitmaps of supported hwpt types of by underlying iommu, indexed > + * by ops->driver_type which is one of enum iommu_hw_info_type. > + */ > +const u64 iommufd_hwpt_type_bitmaps[] = { > + [IOMMU_HW_INFO_TYPE_DEFAULT] = BIT_ULL(IOMMU_HWPT_TYPE_DEFAULT), > +};
I am a bit confused here. Why do you need this array? What I read is that you want to convert ops->driver_type to a bit position in cmd->out_hwpt_type_bitmap.
Am I getting it right?
If so, why not just cmd->out_hwpt_type_bitmap = BIT_ULL(ops->driver_type);
?
Best regards, baolu
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